Method and apparatus for recording optical information, and optical disk

ABSTRACT

A method of recording data optically to an optical disk having a plurality of sectors, in which each sector has a region to be recorded with data, the data is recorded in units of blocks, and the block includes a predetermined number of sectors and is a data unit including error correction codes. In recording data related to a content by dividing and recording the data in a plurality of sectors continuously, dummy data to be used for extracting a clock in PLL for data reproduction is recorded on a region adjacent before a sector from which data recording is started. The data related to the contents is recorded on sectors following the region recorded with the dummy data.

This application is a divisional application of U.S. patent applicationSer. No. 11/152,508, filed Jun. 15, 2005, which is a divisionalapplication of U.S. patent application Ser. No. 10/078,699, filed Feb.21, 2002, now U.S. Pat. No. 6,985,426.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to a data recording method used in an apparatusfor recording information onto an optical disk by emitting a laser beamto the optical disk.

2. Related Art

Recently, optical disks have become highly desired to be used for visualapplication, and thus it is desired that optical disks be capable ofmass storage and be able to be accessed at a high speed. For thispurpose, there needs to develop an art capable of recording moremicroscopic information. Further, it is important to reduce an overheadregion which is a portion that does not directly contribute to thecapacity such as an address region.

FIG. 10 is a view illustrating a physical sector structure on a track ofa conventional optical disk. As shown in FIG. 10, the optical disk has asector 901 which includes an address region 902 indicating addressinformation and a data region 903 to/from which information can berecorded/reproduced. The data region 903 is located in both a groovetrack 904 and a land track 905 between the groove tracks. The addressregion 902 includes a header region 906 and a mirror region 907. Theheader region 906 is used to record concavo-convex pits which areproduced when the optical disk is manufactured, and can not bere-written.

FIG. 11 shows a sector format. As described above, the sector includesthe address region 902 and the data region 903. The address region 902includes a header region 906 of 128 bytes and a mirror region 907 of 2bytes. The data region 903 includes 2418 bytes of user data region 1007used to record user data, 68 bytes of clock extraction region 1006, and81 bytes of buffer region 1008. The clock extraction region 1006 is usedfor a PLL (Phase Locked Loop: to generate a clock with frequency andphase locked to an input signal) to input the signal for extracting theclock at data reproduction, and is used to absorb a deterioration of afront portion caused by iterative data recording. The buffer region 1008is used to absorb a position shift at data recording or a deteriorationof an end portion caused by repeated data recording.

To record 2418 bytes of data in the user data region of one sector, theabove described optical disk needs 128 bytes of header region, 2 bytesof the mirror region, 68 bytes of clock extraction region, and 81 bytesof buffer region. Accordingly, 2697 bytes length in total is needed fora sector. The data portion includes a portion for error correction, andtherefore a sector needs 2697 bytes length to store 2048 bytes of data.At that time, a utilization ratio of the disk (format efficiency) forrecording a signal on the disk is 75.9% (=2048/2697). This means thatthe format includes 24.1% of redundancy.

For example, in order to record 4.7 GB of data, more data has to berecorded on a unit area with 75.9% of format efficiency than that neededin the recording with 100% of format efficiency. The quality ofreproduction signal with 75.9% of format efficiency deteriorates lessthan that with 100% of format efficiency. To reduce the redundancy,there is a method to reduce a length of the clock extraction region 1006in the data region. However, this method causes a problem that itbecomes difficult to extract the clock used for data reproductionoperation in PLL in a front portion of a series of data.

SUMMARY OF THE INVENTION

The present invention is directed to solve the above described problem.It is an object of the invention to provide a data recording method andapparatus capable of providing a stable operation of PLL which generatesa phase-locked clock, even though a region from which PLL inputs asignal used to lock phase and frequency of the clock is reduced forimprovement of a disk utilization ratio in recording signal (data) onthe optical disk.

In a first aspect of the invention, provided is a method of recordingdata optically onto an optical disk. The optical disk has a plurality ofsectors, each sector having a data region used to record data. The datais recorded in units of blocks, the block is a data unit which includesa predetermined number of sectors and to which error correction isapplied.

According to the method, in recording data related to a content bydividing and recording the data on a plurality of continuous sectors,dummy data is recorded on a region adjacent before a sector from whichdata recording is started, and the data related to the contents isrecorded on sectors following the region recorded with the dummy data.The dummy data is used for extracting a clock for data reproduction.

The region adjacent before on which the dummy data is recorded may be asector adjacent before the sector from which data recording is started,or a region between the blocks.

Further, the dummy data may be recorded on front and/or end portions ofeach sector on which the data is recorded.

Further, the dummy data may include a synchronizing pattern with asingle frequency, or iteration of predetermined patterns.

Further, when a region used to record data of the optical disk isdivided into a plurality of zones each having a different rotationalspeed of the disk at data reproduction, the region on which the dummydata is recorded may be in the vicinity of the most inside area in eachzone.

Further, when the data recording is suspended during the recording ofdata related to the content, the dummy data may be recorded on a regionadjacent before a sector from which the data recording of data relatedto the content is re-started.

Further, the dummy data recorded adjacent before the leading blockincluded in the contents may be longer than the dummy data recordedadjacent before each block included in the contents.

Further, the dummy data recorded adjacent after the final block includedin the contents may be longer than the dummy data recorded adjacentafter each block included in the contents.

In a second aspect of the invention, provided is an apparatus forrecording data optically onto an optical disk. The optical disk has aplurality of sectors. Each sector has a data region used to record data.The data is recorded in units of blocks. The block is a data unit whichincludes a predetermined number of sectors and to which error correctionis applied.

The apparatus includes a recording unit that optically records the dataonto the optical disk, and a controller that controls the recordingoperation of the recording unit.

In recording data related to a content by dividing and recording thedata in a plurality of continuous sectors, the controller controls therecording unit such that dummy data to be used for extracting a clockfor data reproduction is recorded on a region adjacent before a sectorfrom which data recording is started, and that the data related to thecontents is recorded on sectors following the region recorded with thedummy data.

In a third aspect of the invention, provided is an optical disk torecord data optically, having a plurality of sectors, each sector havinga data region used to record data. The data is recorded in units ofblocks. The block is a data unit which includes a predetermined numberof sectors and to which error correction is applied.

In recording data related to a content by dividing and recording thedata on a plurality of continuous sectors, dummy data is recorded on aregion adjacent before a sector from which data recording is started,the dummy data is used for extracting a clock for data reproduction. Thedata related to the contents is recorded on sectors following the regionrecorded with the dummy data.

According to the invention, recording the dummy data on the sectoradjacent before the sector from which data reproduction is startedallows a stable operation of extracting the clock in PLL even though thelength of the clock extraction region is reduced or eliminated.

Recording the dummy data to the front portion of sector storing the dataallows the clock extraction in PLL, as well as recording on the sectoradjacent before the sector from which data reproduction is started, tobe quickly recovered by reproducing the dummy data region, even thoughthe clock extraction in PLL becomes unstable when the optical beampasses through the address region. Also, in iterative data recording, itis possible to absorb the deterioration of recording layer which extendsfrom the front portion of the sector at which a deviation of theincident laser power is large.

Further, recording the dummy data on end portion of the sector storingthe data allows a position shift occurred at data recording to beabsorbed. Also, in iterative data recording, it is possible to absorbthe deterioration of recording layer which extends from the frontportion of the sector at which a deviation of the incident laser powerat iterative data recording is large.

The dummy data can be a single frequency synchronizing pattern toextract the clock, thus to provide a stabler operation of extracting theclock in PLL.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative view of a physical sector structure on a trackof an optical disk according to the invention;

FIG. 2 is an illustrative view of an another physical sector structureon a track of an optical disk according to the invention;

FIG. 3A is an illustrative view of a sector configuration, and

FIG. 3B is a view showing the address region and the data region;

FIG. 4 is an illustrative view of a logical sector configuration inwhich a mirror region is provided to each block;

FIG. 5 is a block diagram of a recording apparatus for an optical diskaccording to the invention.

FIG. 6 shows an optical disk in which a plurality of zones are provided;

FIG. 7 is an illustrative view of sector format in the invention;

FIGS. 8A to 8F are illustrative views showing various recording modes ofrecording the dummy data (First Embodiment);

FIGS. 9A to 9C are illustrative views showing recording modes ofrecording the dummy data in case that the address region is not provided(Second Embodiment);

FIG. 10 is an illustrative view of a physical sector structure on atrack of an optical disk in the prior art; and

FIG. 11 is an illustrative view of a sector format in the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The description is made to a data recording method of an optical disk inpreferred embodiments of the invention below.

First Embodiment

<Track Configuration of Optical Disk>

FIG. 1 is a view illustrating a physical sector structure on a track ofan optical disk of the invention. As shown in FIG. 1, the optical diskhas a groove track 101 and 103 and a land track 102 between the groovetracks. A sector 104 which is an information unit includes an addressregion 105 and a data region 106. The address region 105 includes aheader region 108 and a mirror region 109. The header region 108 is usedto record concavo-convex pits which are produced when the optical diskis manufactured, and can not be re-written. The data region 106 islocated in both a groove track 101 and a land track 102.

In FIG. 1, a group of concavo-convex pits 110 is located on a borderline between the land track 102 and the groove track 101 or 103 so thatthe group of concavo-convex pits 110 can be detected from either of theland track 102 and the groove track 103. The arrangement of the group ofconcavo-convex pits 110 is not limited to this. The group ofconcavo-convex pits 110 may be located at a center of each track, asshown in FIG. 2. Even in this case, the address region or the dataregion may be located at either one of the groove track and the landtrack.

FIGS. 3A and 3B are illustrative views of a sector configuration of theoptical disk shown in FIG. 1. In FIG. 3A, the track 301 includes aplurality of sectors 302 to 311. Four sectors 303 to 306 compose oneblock 312. Similarly four sectors 307 to 310 compose one block 313. The“block” is a unit for data recording that includes error correctioncodes, and a data unit in which error correction to the data can becompleted by itself. Data is recorded or reproduced in units of blocks.Each sector 302, 303, includes the address region and the data region asdescribed above. For example, the sector 304 includes a forehand addressregion 304A and a following data region 304D (see FIG. 3B). Although inthis embodiment address information of the sector is recorded by theconcavo-convex pits 110, any other methods can be used to record theaddress information as long as the data region is separated by theaddress region.

In this embodiment, four sectors compose one block, and one blockaddress is detected by reproducing address regions of four sectors. Thisconfiguration can reduce an address region of each sector compared tothe prior art (see FIG. 7), thus to increase data storage capacity. Inthe data region, information is recorded as pits after modulatedaccording to a predetermined modulation method. The pits can be formed,for example, by changing optics of a material of a recording layer inaccordance with an emitted power of the laser beam varied strongly andweakly.

As described above, in this embodiment, four sectors compose one block,and one block address is detected by reproducing address regions of allof the four sectors. The number of sectors composing one block may beany number other than four. The block address may be detected byreproducing address regions in some of all sectors composing one block.

It is noted that it needs to recognize a leading sector in order todetect one block address by reproducing address regions of a pluralityof sectors. For this purpose, as shown in FIG. 4, mirror regions 314,315 and 316 may be provided to each block. The length of the mirrorregion 314, 315 or 316 shown in FIG. 4 is equal to or more than twicethe length of the mirror region 109 shown in FIG. 1. By providing thelong mirror region to each block as described above, in conversion of apit train of the concavo-convex pits 110 in the address region intopatterns (for example, a pit train of “concave”, “convexity” and“concave” is converted into “1”, a pit train of “convexity”, “concave”and “convexity” is converted into “0”, and a pit train of “convexity”,“convexity” and “concave” is converted as “a head of block”), it becomesneedless to provide a pattern to indicate a head of sector. This allowsthe number of patterns to be reduced, and a reading rate indicating aprobability of correctly reading patterns other than that pattern to beimproved.

<Configuration of Recording Apparatus>

FIG. 5 is a block diagram of a recording apparatus (it is referred to as“an optical disk drive” below) of optical information according to theinvention. The optical disk drive 500 is an apparatus for recordinginformation onto the optical disk 501, and includes a spindle motor 502,an optical head 503, a laser beam control circuit 504, a servo circuit505, a reproduction signal digitizing circuit 506, a digital signalprocessing circuit 507, a recording compensation circuit 508, and CPU509. The optical disk drive 500 is connected to a host PC 510.

The spindle motor 502 is a motor which rotates the optical disk 501. Theoptical head 503 emits the laser beam onto the optical disk 501 andconverts the reflected beam from the disk 501 into an electrical signalto output the signal as a reproduction signal. The beam control circuit504 controls a power of the laser beam emitted from the optical head503. This control is executed according to instructions from the CPU509.

The servo circuit 505 performs position control of the optical head 503,focus and tracking control, and rotation control of the spindle motor502. The reproduction signal digitizing circuit 506 amplifies anddigitizes the reproduction signal from the optical head 503 to generatea digitized signal. An internal PLL (not shown) generates a clock signalin sync with the digitized signal.

The digital signal processing circuit 507 executes a predetermineddemodulating process and address retrieving process to the digitizedsignal in the address part, at an address reading. At a datareproducing, the digital signal processing circuit 507 executes apredetermined demodulating process and error correcting process to thedigitized signal in the data part to generate a reproduction data. Indata recording, the digital processing circuit 507 executes a process toadd error correction code and a predetermined demodulating process todata to be recorded to generate a modulated data. The digital processingcircuit 507 also generates dummy data which is described below.

The recording compensation circuit 508 converts the modulated data intooptical modulated data that is composed of a series of pulses, andfurther controls subtly pulse widths of the optical data to generate arecording pulse signal suitable for forming pits. The CPU 509 controls awhole of the optical disk drive. The host 510 may be composed of acomputer hardware (not shown), application software (not shown), andoperating system (not shown), and requests recording/reproducingonto/from the optical disk 500.

<Operation of Recording Apparatus>

With reference to FIGS. 3A, 3B and 5, the description is made tooperations to reproduce/record data from/onto the optical disk 500. Itis noted that the following description is made with an example in whicha continuous data recording of one content is started from a sector 307(that is, block 313) in a track 301 shown in FIG. 3A.

When the host PC 501 provides the CPU 509 with a data recording request(the request is for recording data in the block 313.), the servo circuit505 moves the optical head 503 to the vicinity of the sector which hasan address indicated by the data recording request.

The digital signal processing circuit 507 starts address readingaccording to the digitized signal which is obtained via the optical head503 and the reproduction digitizing circuit 506, and reads out theaddresses of sectors 303 to 306 to determine the block address of theblock 312 and expect the block address of the block 313. Then, dummydata (dummy signal) is recorded at the sector 306 located in front ofthe block 313 on which data is to be recorded. A pattern suitable forPLL to extract the clock is used as the dummy data. It becomes possiblefor PLL to extract the clock from the dummy data, by recording the dummydata on the final sector 306 of the block 312 located in front of theblock 313 on which data is to be recorded. Thus, a stable operation togenerate the clock by PLL can be achieved even though the region forextracting the clock in PLL is eliminated or reduced.

Subsequently, the address of the sector 307 is read and compared withthe address expected from the adjacent before block. When the readaddress matches the expected address, data recording is started from thesector 307. It is noted that the expected address information isinformation indicating presence or absence of the address region in apredetermined reproduction timing, or information relating to a whole orpartial conformity between the respective pit train and the expected pittrain. During this operation, the beam control circuit 504 controls thelaser beam emitted from the optical head 503 so that the laser beam hasa predetermined power level instructed by the CPU 509. After recordingon the sector 307, a predetermined data is recorded on the sectors 308to 310 while addresses are sequentially read.

Next, the description is made to the reproducing operation. Similar tothe recording operation, in the reproducing operation, addresses ofsectors 303 to 306 are read out, and then the dummy data recorded on thesector 306 is reproduced. The reproduction signal digitizing circuit 506amplifies and digitizes the reproduction signal from the optical head503 to generate the digitized signal. During this operation, theinternal PLL generates a clock signal synchronized with the digitizedsignal. While holding the state of extracting the clock, the PLL readsan address of the sector 307, and then reproduces data recorded on thesector 307.

In case that data is recorded from inside to outside of the optical disk501, the track 301 becomes a track in vicinity of the most inside trackin all of the data regions, and no data is recorded inside of the track301.

Alternatively, as shown in FIG. 6, in case that an area used to recorddata of the optical disk is divided into a plurality of zones (forexample, for ZCLV control), the track 301 is the most inside track ofeach zone 602, 603 or 604, or a track located in vicinity of the mostinside track. No data is recorded inside of the track 301 in each zone.In the optical disk 501 shown in FIG. 6, data area is divided into threezones. A rotational speed of the spindle motor 502 in each zone isdifferent from each other so that the substantially same linear velocitycan be obtained in all zones.

<Example of Sector Configuration>

FIG. 7 shows a sector configuration of the optical disk according to theinvention. The sector 801 includes an address region 802 and a dataregion 803. The address region 802 has 24 bytes of header region 804 and12 bytes of mirror region 805. A length of the address region 802 isdetermined to be smaller than that of the sector in the prior art shownin FIG. 11. In this embodiment, one block address is detected byreproducing four sector address regions, and the dummy pattern forextracting the clock is recorded on the final sector of the blockadjacent before the block to record data, and therefore it is possibleto extract the clock with a small length of the address region.

The data region 803 includes 13 bytes of front data region 806, 2418bytes of user data region 807, and 13 bytes of rear data region 808. Thefront data region 806, the user data region 807, and the rear dataregion 808 are used ordinary as one to store the user data. As required,the front data region 806 may be used as the clock extraction region1006 shown in FIG. 11, and the rear data region 808 may be used as thebuffer region 1008 shown in FIG. 11. Data lengths of those regions 806and 808 may preferably set to be smaller than those of regions 1006 and1008 shown in FIG. 11 respectively to improve the format efficiency.

<Variations of Recording Mode of Dummy Data>

Next, the description is made to variations of recording mode of thedummy data. FIGS. 8A to 8F are views showing different recording modesof the dummy data, respectively. In each recording mode, four sectorscompose one block. For example, in the recording mode of FIG. 8A, eachblock 707, 708, 709 or 710 includes four sectors. In FIGS. 8A to 8F, ahatched portion of the sector means a portion on which the dummy data isrecorded. The data D1, D2, D3 and D4 compose one content X, and the dataD5, D6, D7 and D8 compose another content Y.

The recording mode shown in FIG. 8A is the recording mode describedabove with reference to FIGS. 3 and 5. In this recording mode, forrecording data D1, D2, D3 and D4 of content X on each sector in theblock 708, the dummy data is recorded on the final sector P of the block707 located in front of the block 708 to be recorded with data. Thedummy data is recorded on the whole data region 803 in the sector P. Itis noted that, in order to record data in each sector, addressinformation of a sector is first read, and then data is recorded in thesector of which address information has been read.

The recording mode shown in FIG. 8B shows a recording mode in which thedummy data is recorded on a front portion of the data region in additionto the sector before the region to be recorded with the content data.That is, in the data region 803, the front data region 806 is used asthe clock extraction region and recorded with the dummy data, the otherregions 807 and 808 are recorded with user data. For recording data D1,D2, D3 and D4 on each sector in the block 712, the dummy data isrecorded on the final sector P of the block 711 before the block 712 tobe recorded with data, and is further recorded on the front portion(front data region 806) of each data region storing data D1, D2, D3 orD4. Recording the dummy data on the front portion of sector storing thedata allows an operation of extracting the clock in PLL to be quicklyrecovered by reproducing the region carrying the dummy data, even thoughthe clock extracting operation in PLL becomes unstable when the opticalspot passes through the address region. Also the deterioration ofrecording layer which proceeds from the front portion of the sector atwhich a deviation of the incident laser power at iterative datarecording is large can be absorbed.

The laser power emitted for recording is five to ten times the laserpower emitted for reproduction, and therefore a deviation of the emittedlaser powers becomes maximum at an interface of the address region andthe data region, resulting in the deterioration of recording layer dueto repeat of thermal expansion and shrink. To exclude thisdeterioration, it is preferable to use a higher power to reproduce theaddress region during the data recording operation than the power usedin the ordinal reproducing operation.

The recording mode shown in FIG. 8C shows a recording mode in which thedummy data is recorded on front and end portions of the data region inaddition to the sector before the region to be recorded with the contentdata. That is, in the data region 803, the front data region 806 is usedas the clock extraction region and the rear data region 808 is used asthe buffer region. These regions 806 and 808 are used to record thedummy data, and the user data region 807 is used to record the userdata. For recording data D1, D2, D3 and D4 to each sector in the block716, the dummy data is recorded on the final sector P of the block 715before the block 716 to be recorded with data and is further recorded onthe front portion (front data region 806) and end portion (rear dataregion 808) of each data region storing data D1, D2, D3 or D4.

Recording the dummy data on the front portion of sector storing the dataD1 to D4 allows the operation of extracting the clock in PLL to bequickly recovered by reproducing the dummy data region, even though theclock extracting operation in PLL becomes unstable when the optical beampasses through the address region. Also, in iterative data recording, itis possible to absorb the deterioration of recording layer which extendsfrom the front portion of the sector at which a deviation of theincident laser power is large. Further recording the dummy data in endportion of the sector storing the data allows a position shift occurredat data recording to be absorbed. Also, in iterative data recording, itis possible to absorb the deterioration of recording layer which extendsfrom the front portion of the sector at which a deviation of theincident laser power is large.

The recording mode shown in FIG. 8D shows a recording mode in which datarecording is suspended in the middle of the block. When recording dataD1, D2, D3 and D4 on each sector in the block 720, the dummy data isrecorded on the final sector P1 of the block 719 before the block 720 tobe recorded with the data. Subsequently the data D1 and D2 are recorded.Then, when the address of the block 720 can not be detected due to acertain cause and thus the data recording is suspended, the address ofthe following block is detected. When the address of the block (here,block 721) is detected, the final sector P2 of the block 721 is recordedwith the dummy data, and subsequently each sector of the block 722 isrecorded with data D1, D2, D3 and D4.

As described above, when data recording is suspended due to a certaincause and then re-started, recording the dummy data in the sector infront of the sector from which data recording is re-started. Thus, theclock extracting operation in PLL can be quickly recovered byreproducing the dummy data, even though the clock extracting operationin PLL becomes temporally unstable due to defects produced on themanufacture.

The recording mode shown in FIG. 8E is a mode for recording a pluralityof contents. Here, an example for recording the content X including dataD1, D2, D3 and D4, and the content Y including data D5, D6, D7 and D8.

Similar to the recording mode shown in FIG. 8A, the dummy data isrecorded on the final sector P of the block 723 before the block 724 tobe recorded with the data D1 to D4 of the content X, and subsequentlydata D1, D2, D3 or D4 is recorded on the respective sector of the block724. Data D5, D6, D7 and D8 as the content Y is recorded on therespective sector of the block 725 following the block 724 on which dataD1, D2, D3 and D4 are recorded. When data following the data D5 isreproduced, an operation of extracting the clock in PLL is performedwhile dummy data in the block 723 or the block 724 is reproduced, andthen the following data is reproduced while a state of the clockextracting operation in PLL is being held.

In this recording mode, when new data is recorded in connection with thesector with data which has not been recorded yet, the dummy data isfirst recorded, while when new data is recorded in connection with thedata which has been already recorded, the dummy data is not recorded.This can increase storage capacity of user data.

FIG. 8F is a view explaining another recording mode for recording aplurality of contents. In the recording mode shown in FIG. 8F, the finalsector P1 of the block 727 is recorded with the dummy data and then eachsector of the block 728 is recorded with the data D1, D2, D3 and D4 ofthe content X. Subsequently, when the content Y is recorded, the dummydata is recorded on the final sector P2 of the-data block 729 followingthe block 728 carrying the data D1 to D4 of the content X, and then thedata D5, D6, D7 and D8 is recorded on each sector of the block 730.

In this recording mode, when data of new content Y is recorded inconnection with the data which has been already recorded, the dummy datais recorded on the sector adjacent before the sector from which datarecording of the new content (Y) data is started. Thus, a stable clockextracting operation in PLL can be achieved by reproducing the dummydata, even in the case that data recording state or modulation method islargely different, that a zone is changed, or that the linear velocityor recording density is largely different, between two contents X and Y.

It is noted that the recording mode shown in FIG. 8E and 8F may beswitched and used for each disk or data. In this case, information ofswitching recording mode for each data is stored to a specific region ofthe disk (for example, a region capable of recording in the controltrack 601 in FIG. 6), or a recording apparatus.

At the border sectors between two different contents, excluding the casethat the recording statuses are largely different, the case that themodulation methods are different, and the case that the linear velocityor recording density is different, the recording mode of FIG. 8E has ahigh possibility of reproduction even though it takes a long rotationalwaiting time, by extracting the clock in PLL from a sector which is infar front of the target sector or by repeating the above described stepsa plurality of times. Accordingly, it is suitable for the case thatcontinuous data recording in one location is possible, or the case thata memory can cope with a problem relating to the long rotational waitingtime even though data is recorded on a plurality of regions.

On the contrary, in the recording method shown in FIG. 8F, data that isused to extract the clock in PLL is recorded on the sector adjacentbefore the sector from which data recording of a new data is started.This allows data to be reproduced more surely in a short rotationalwaiting time. This is suitable for the case that data is recordeddistributively on a plurality of regions or the case that the memorydoes not have a enough capacity to cope with the long rotational waitingtime. It is noted that the memory is provided with the host PC 510 shownin FIG. 5 and stores temporally the data from the digital processingcircuit 507.

The format efficiency is determined below for the recording mode inwhich the dummy data is recorded on both front and end portions of dataregion as shown in FIG. 8C. Referring to FIG. 7, for recording 2418bytes of data on the user data region 803 of the sector 801, requiredare 24 bytes of header region 804, 12 bytes of mirror region 805, 13bytes of front data region 806, and 13 bytes of rear data region 808.Accordingly, 2480 bytes length in total is needed for a sector. The datastored in the user data region includes a portion for error correction,and therefore a sector needs 2480 bytes length to store 2048 bytes ofdata. At that time, a utilization ratio of the disk (format efficiency)for recording signal on the disk is 82.5% (=2048/2480). This means thatthe format efficiency is largely improved compared to the prior art(75.9%) shown in FIG. 10. Recording not dummy data but user data to thefront data region 806 and the rear data region 808 as shown in FIGS. 8Aand 8B results in more improvement of the format efficiency.

As described above, recording the dummy data on the sector adjacentbefore the sector to be recorded (reproduced) with data allows thelength of the region (corresponding to front data region 806 and reardata region 808) for extracting the clock in PLL in the sector to berecorded with data to be eliminated or reduced drastically. That is,recording the dummy data on the sector (P, P1) adjacent before thesector from which data is reproduced can provide a stable operation ofextracting the clock in PLL even though the length of the region forextracting the clock is eliminated or reduced. It is noted that althoughin FIG. 7 the mirror region 805 is allocated after the header region804, the mirror region 805 may be allocated before the header region804. By allocating it before the header region 804, the position of theheader region 804 can be easily specified. Particularly, address readingcan be started rapidly at start-up or after jump from a position on adifferent radial.

In this embodiment, the dummy data is recorded on the sector adjacentbefore the sector from which data reproduction is started. However, thedummy data may be recorded on a plurality of sectors including theadjacent before sector and sectors located before the adjacent beforesector, if a stable operation of extracting the clock in PLL can beachieved to the following sectors to be reproduced. This allows a marginfor extracting the clock in PLL to be extended.

Similarly, in this embodiment the dummy data is recorded on the wholedata region in the sector adjacent before the sector from which datareproduction is started. However, the dummy data may be recorded on aportion of the sector including a end portion, for example, a latterhalf portion, if a stable operation of extracting the clock in PLL canbe achieved to the following sectors to be reproduced.

The dummy data may be a pattern capable of extracting the clock, andmore preferably be a pattern with a single frequency. By using thesingle frequency pattern, a stabler operation of extracting the clock inPLL can be achieved. Further the dummy data may be a pattern includingiteration of a predetermined pattern.

Second Embodiment

<Recording Mode of Dummy Data With No Address Region>

In the above embodiment, the description has been made to the case thatthe address region carrying address information is provided between thedata regions. However the address region may not be provided between thedata regions when the address information can be detected without theaddress region, for example, when address information is superimposed onthe wobble of the track. That is, in the format shown in FIG. 7, onesector may include only the data region 803.

The recording mode of the dummy data when the address region is notprovided is described below in detail with reference to FIGS. 9A to 9C.

FIGS. 9A to 9C show different recording modes of the dummy data,respectively. For example, in FIG. 9A, the block 1104 or 1105 iscomposed of four sectors. In FIGS. 9A to 9C, hatched portion indicates aregion to which the dummy data is recorded.

In the recording mode of FIG. 9A, the dummy data is recorded on a gapregion 1103 between the blocks 1104 and 1105 before recording the dataD1 to D4 to each sector in the block 1105. The length of the gap region1103 may preferably be shorter than that of the sector 1102. Making theregion 1103 shorter than the sector 1102 allows the data region to belarger, resulting in a mass storage optical disk.

In the recording mode of FIG. 9B, the dummy data is recorded on a gapregion 1108 between the blocks 1110 and 1111 before recording the dataD1 to D4 in each sector of the block 1111. Then data D1 to D4 arerecorded, and subsequently the dummy data is recorded on the region 1109adjacent after the block 1111. The dummy data recorded on the region1108 and the dummy data recorded the region 1109 may be different indata pattern or data length. It is possible to determine a leading ofthe block by reproducing the dummy data with different data pattern ordata length. Regarding the dummy data recorded on the regions 1108 and1109, when the respective dummy data includes a plurality of patternseach having a different data pattern, the respective dummy data may havea common pattern portion of which data pattern or data length is incommon with those dummy data. The common pattern portion allows aconfiguration of an apparatus for recognizing a pattern to be simple.

Next, the description is made to the recording mode of FIG. 9C, in whichdata D1 to D12 compose a content.

The dummy data is recorded on a gap region 1114 between the blocks 1122and 1123 before recording the data D1 to D4 to each sector on the block1123. Then, the dummy data is recorded on the gap region 1116 betweenthe blocks 1123 and 1124 after recording the data D1 to D4 on the block1123.

Next, for recording data D5 to D8 on each sector in the block 1124,prior to a record of data D5 to D8, the dummy data is recorded on thegap region 1117 between the blocks 1123 and 1124. Then, the dummy datais also recorded on the gap region 1118 between the blocks 1124 and 1125after recording the data D5 to D8.

Similarly, the dummy data is recorded on a gap region 1119 between theblocks 1124 and 1125 before recording the data D9, D10, D11 and D12 ineach sector of the block 1125. Then, the dummy data is also recorded oneach of the region 1120 and 1121 between the blocks 1125 and 1116 afterrecording the data D9, D10, D11 and D12.

Patterns or lengths of data recorded on the region 1115, 1117 and 1119are the same, and patterns or lengths of data recorded on the region1116, 1118 and 1120 are the same. As a matter of convenience, in thefollowing description dummy data is referred to with the same numeralreference as that indicating the gap region which stores the dummy data.

If each data in a first group including the dummy data 1115, 1117 and1119 can be distinguished from each data in a second group including thedummy data 1116, 1118 and 1120, length or start position of each dummydata can be varied randomly. For example, length or start position ofeach dummy data 1115, 1117 or 1119 may be varied randomly by a severaltimes of the reference clock to be recorded. Thus, when a plurality ofrecordings are performed on the same region, a region highly heated upmay be changed subtly at each recording and therefore deterioration ofthe recording layer can be reduced.

The dummy data 1114 recorded before the leading block 1123 of thecontent A may be longer than the dummy data 1115, 1117 or 1119 recordedadjacent before each block in the content A. That is, when content Aincludes data D1 to D12, the dummy data 1114 is recorded before thedummy data 1115 and is set to be different from the other dummy data indata length and data pattern. This allows the start position of thecontent A to be recognized by reproducing the dummy data 1114.

The dummy data 1121 recorded after the final block 1125 of the content Amay be longer than the dummy data 1116, 1118 or 1120 recorded adjacentafter each block in the content A. That is, when content A includes dataD1 to D12, the dummy data 1121 is recorded after the dummy data 1120recorded after the final data D12 of the content A and is set to bedifferent from the other dummy data in data length and data pattern.This allows the end position of the content A to be recognized byreproducing the dummy data 1121.

According to this embodiment, the dummy data exists in a region betweenthe block 1125 and the block 1126. This enables a quality deteriorationof the data D12 recorded on the block 1125 to be suppressed even thoughthe recording power varies when the recording of the next content isstarted from the block 1126.

As described above, the dummy data is recorded before the recording unit(block) containing the error correction codes, while in the recordingunit (block) containing the error correction codes, no dummy data or arelatively small length of the dummy data is recorded. This can resultin improvement of the format efficiency and a stable operation ofextracting the clock in PLL.

It is noted that the concept of this embodiment can be applied to thefist embodiment in which an address region is provided between dataregions by reading a gap region as a sector. Further it is noted thatthe concept of the first embodiment of the invention described withreference to FIG. 7 can also be applied to this embodiment.

Although the present invention has been described in connection withspecified embodiments thereof, many other modifications, corrections andapplications are apparent to those skilled in the art. Therefore, thepresent invention is not limited by the disclosure provided herein butlimited only to the scope of the appended claims.

The present disclosure relates to subject matter contained in JapanesePatent Application No. 2001-047855, filed on Feb. 23, 2001, which isexpressly incorporated herein by reference in its entirety.

1. An information recording medium storing: data that is recorded in ablock which includes a plurality of sectors; first dummy data that isrecorded on an area just before the block; second dummy data that isrecorded on an area just after the block; and end dummy data that isrecorded on an area just after the second dummy data, wherein the firstdummy data, the second dummy data and the end dummy data are differentin data length and include a same data pattern, and the second dummydata further includes a data pattern different from the same datapattern.
 2. A method of reproducing data from an information recordingmedium according to claim 1, the method comprising: reproducing thefirst dummy data; and reproducing the data.
 3. A method of recordingdata to an information recording medium, the method comprising: whenrecording data in a block which includes a plurality of sectors,recording first dummy data on an area of the information recordingmedium; recording the data on an area of the information recordingmedium just after the area of the first dummy data; recording seconddummy data on an area of the information recording medium just after thedata; and recording end dummy data on an area of the informationrecording medium just after the area of the second dummy data, whereinthe first dummy data, the second dummy data and the end dummy data aredifferent in data length and include a same data pattern, and the seconddummy data further includes a data pattern different from the same datapattern.